fix(compile): preserve Redis class helper captures

changelog.d/10660-cjs-multiline-var-hoist.md

@@ -0,0 +1 @@
+- Fixed CommonJS class hoisting when a comma-separated `var` declaration continues across lines. Classes such as Redis's `RedisClient` now remain inside their module factory when they capture private-field helper variables declared on later lines, preserving the initialized helper bindings at runtime. (#10660)

crates/perry/src/commands/compile/cjs_wrap/hoist_classes.rs

@@ -808,9 +808,10 @@ fn collect_top_level_let_const_var_names(source: &str) -> Vec<String> {
             continue;
         };
         let mut q = p + kw_len;
-        // Walk through one or more comma-separated declarators on the same
-        // logical line. Stop at `=` (initializer), `;`, or the end of line
-        // (semicolon optional in JS).
+        // Walk through one or more comma-separated declarators. A comma may
+        // continue the declaration onto another physical line (as emitted by
+        // TypeScript for long lists of private-field helpers). Otherwise a
+        // top-level newline ends an ASI-terminated declaration.
         loop {
             while q < bytes.len() && (bytes[q] == b' ' || bytes[q] == b'\t') {
                 q += 1;
@@ -874,6 +875,12 @@ fn collect_top_level_let_const_var_names(source: &str) -> Vec<String> {
                     }
                     b',' if inner == 0 => {
                         q += 1;
+                        // A top-level comma proves that another declarator
+                        // follows, so newlines here are continuation
+                        // whitespace rather than ASI boundaries.
+                        while q < bytes.len() && bytes[q].is_ascii_whitespace() {
+                            q += 1;
+                        }
                         break;
                     }
                     b';' | b'\n' if inner == 0 => {

crates/perry/src/commands/compile/cjs_wrap/tests/hoist_scanner.rs

@@ -29,3 +29,31 @@ module.exports = { ChecksumStream };
         "the class declaration must remain at its source position inside the factory"
     );
 }
+
+#[test]
+fn multiline_var_declarator_keeps_dependent_class_in_cjs_iife() {
+    // @redis/client declares its transpiled private-field helpers as one long
+    // comma-separated `var` statement. The later helpers start on new lines;
+    // missing them here hoists RedisClient out of the CommonJS factory and
+    // severs the class methods' captures of those helper functions.
+    let src = r#"var _RedisClient_instances, _a,
+    _RedisClient_options,
+    _RedisClient_isolationPool,
+    _RedisClient_init;
+class RedisClient {
+    connect() { return _RedisClient_isolationPool(this); }
+}
+_RedisClient_isolationPool = function _RedisClient_isolationPool() {};
+module.exports = { RedisClient };
+"#;
+
+    let (blocks, hoisted_names, rest) = extract_top_level_class_decls(src);
+    assert!(
+        !hoisted_names.iter().any(|name| name == "RedisClient"),
+        "a class depending on a continued CJS-local declaration must not hoist; hoisted block:\n{blocks}"
+    );
+    assert!(
+        rest.contains("class RedisClient"),
+        "the dependent class must remain inside the CommonJS factory"
+    );
+}